Method of attaching rail clip anchoring device to a railway rail support

ABSTRACT

In a method of attaching a steel railway rail support (baseplate or sleeper) ( 2 ) to a ductile iron rail clip anchoring device ( 1 ) a boss ( 11 ), extending from the bottom of a body ( 10 ) of the anchoring device ( 1 ), is inserted into a hole ( 20 ) passing through the support ( 2 ) at a location on its surface ( 2   a ) at which the anchoring device ( 1 ) is to be attached until the anchoring device body ( 10 ) abuts the support surface ( 2   a ). The steel around the hole ( 20 ) in a region on the support surface ( 2   b ) opposite to that on which the. anchoring device body ( 10 ) is located is compressed while the anchoring device ( 1 ) is held in place, so that the compressed steel flows plastically against the boss ( 11 ) within the hole ( 12 ), until the force applied to the boss ( 11 ) brings about elongation thereof, whereby the boss ( 11 ) undergoes an elastic set which clamps the boss ( 11 ) to the support ( 2 ).

The present invention relates to a method of attaching a rail clipanchoring device to a railway rail support, such as a railway sleeper orbaseplate.

At present cast iron rail clip anchoring devices, or “shoulders”, areattached to rolled steel baseplates using separate fasteners, forexample bolts and nuts, or by welding. However, owing to the largenumber of shoulder/baseplate assemblies that are required it isdesirable in order to reduce costs to fasten the shoulder to thebaseplate without the additional expense of a separate fasteningcomponent. For the same reason it is also desirable to keep machining ofeither the baseplate or the shoulder to a minimum. Similar problemsarise with attaching shoulders to steel sleepers.

According to a first aspect of the present invention there is provided amethod of attaching a steel railway rail support to a ductile iron railclip anchoring device, which method comprises:

inserting a boss, extending from the bottom of a body of the anchoringdevice, into a hole passing through the support at a location on itssurface at which the anchoring device is to be attached until theanchoring device body abuts the support surface; and

compressing the steel around the hole in a region, on the supportsurface opposite to that on which the anchoring device body is located,while the anchoring device is held in place, so that the compressedsteel flows plastically against the boss within the hole, until theforce thereby applied to the boss brings about elongation thereof,whereby the boss undergoes an elastic set which clamps the boss to thesupport.

This method is quick and simple and has the additional advantages that(a) there is no requirement for a separate fastening component, (b)there is no need to induce heat into either component, (c) there is noneed to clean rust or scale from either component, and (d) the methodcan be performed with common metalworking tools. Furthermore, unlikemethods which simply hold the shoulder in place, a shoulder and supportjoined using this method must undergo stress reversal before they can beseparated.

Preferably, the boss is provided with at least one recess in its flankand the compressed steel also flows plastically into that recess.Desirably, the recess comprises a single non-helical groove extendingaround the boss. Alternatively, the flank of the boss may be providedwith a plurality of recesses, each comprising a non-helical grooveextending around the boss.

The step of compressing the steel around the hole is preferablyperformed by applying a penetrating tool, having a working face ofdesired shape, to the surface of the support opposite to that on whichthe anchoring device body is located until the tool has entered thesleeper surface for a desired distance. The penetrating tool may beshaped to allow the said elongation of the boss.

The step of inserting the boss into the hole in the support may beperformed by supporting the anchoring device so that the boss extendsupwardly and then lowering the support such that the boss passes throughthe hole.

Typically, the support will be provided with two such holes and themethod will be carried out simultaneously with respect to both holesthereby to attach two anchoring devices to the support.

The or each hole may be punched into the steel support.

According to a second aspect of the present invention there is provideda rail clip anchoring device, for use with a method embodying the firstaspect of the present invention, which device has an anchoring devicebody and, extending from the bottom of that body, a boss provided withat least one recess in its flank, the recess comprising a singlenon-helical groove extending around the boss.

According to a third aspect of the present invention there is provided arailway rail fastening assembly comprising a steel railway rail support,having two holes therethrough, and two ductile iron rail clip anchoringdevices, each anchoring device having an anchoring device body and,protruding from the bottom of that body, a boss which extends into arespective one of the said holes in the support, the boss of eachanchoring device having an elastic set whereby the boss is clamped tothe support, wherein the boss of at least one of the anchoring deviceshas at least one recess provided in its flank, the recess comprising asingle non-helical groove extending around the boss. The boss may beprovided with a plurality of recesses, each comprising a non-helicalgroove extending around the boss.

The profile of the or each groove is preferably substantially that of abuttress thread 15. The or each recess is preferably provided adjacent afree end of the boss.

Reference will now be made, by way of example, to the accompanyingdrawings, in which:

FIGS. 1, 2 and 3 show in perspective respective simplifiedrepresentations of a shoulder, a portion of a baseplate and apenetrating tool for use in a method embodying the first aspect of thepresent invention;

FIGS. 4 to 8 illustrate steps in a method embodying the first aspect ofthe present invention;

FIG. 9 shows a typical groove profile used in a shoulder embodying thesecond aspect of the present invention; and

FIGS. 10 to 12 show views of a baseplate/shoulder assembly producedusing a method embodying the first aspect of the present invention.

In a method embodying the first aspect of the present invention aductile iron rail clip anchoring device, hereafter called a shoulder, isattached to a steel baseplate. A simplified representation of a shoulder1 is shown in FIG. 1. The shoulder 1 is a ductile iron casting and has abody 10 from which there extends a cylindrical elongate boss 11 providedaround its flank with a plurality of grooves 12 spaced along its length,the first of the grooves 12 being adjacent to the free end 13 of theboss 11. The boss 11 may be of any length less than or equal to thethickness of the baseplate 2 to which the shoulder 1 is to be attachedand can be of any cross-sectional shape, although for ease ofmanufacture a cylindrical cross-section is preferred.

A simplified representation of a portion of a rolled steel baseplate 2to which the shoulder 1 of FIG. 1 may be attached is shown in FIG. 2,the baseplate 2 having a throughhole 20 of cylindrical cross-section.Each baseplate 2 will have two such holes 20, preferably formed bypunching through the baseplate 2, at locations corresponding to thedesired positions of the respective shoulders 1 to be fastened to thebaseplate 2. The baseplate 2 has a top face 2 a and a bottom face 2 b.

In a method embodying the first aspect of the present invention, asshown in FIG. 4 firstly two shoulders 1 (only one shown throughout) areheld in a fixture jig 4 (not shown in FIG. 4) such that their respectivebosses 11 extend upwardly. The baseplate 2 is then positioned, with itstop face 2 a facing downwards, as shown in FIG. 5, such that the holes20 therein slip over the bosses 11 and the top face 2 a of the baseplate2 makes contact with the respective bodies 10 of the shoulders 1. Usinga press (not shown), for example a mechanical or hydraulic metal workingpress of around 200 ton (203.21 tonnes) capacity, a penetrating tool 3is brought into contact with the bottom face 2 b of the baseplate 2, asshown in FIG. 6. As shown in FIG. 3 the tool 3 is similar to a hollowpunch, having a circular working face 30 and a void 31. The working face30 of the tool 3 is chosen so as to be a little larger in diameter thanthe hole 20 in the baseplate 2 and in use is brought into contact withthe region of the bottom face 2 b of the baseplate 2 around the hole 20.As shown in FIG. 7 the press forces the tool 3 against the bottom face 2b of the baseplate 2 until the shear strength of the baseplate materialis exceeded, whereupon the working face 30 of the tool 3 penetrates thebottom face 2 b for a predetermined distance. As a result, steel in theregion of the baseplate 2 where the tool 3 has penetrated flowsplastically into the grooves 12 and exerts a compressive force againstthe flank of the boss 11 which acts in such a way that the boss 11deforms, i.e. stretches. Since the boss 11 is constrained at one end bythe body 10 of the shoulder 1 held in the fixing rig 4, the boss 11 canstretch only upwardly, towards the opening of the hole 20 in the bottomface 2 b of the baseplate 2. The void 31 is provided in the tool 3 toallow for this to happen while the tool 3 is being pressed into thebaseplate 2. The stretching of the boss 11 results in an elastic set inthe boss 11, which remains after the penetrating tool 3 is backed off,and produces a restoring clamping force, similar to that provided by abolt, which holds the shoulder 1 on the baseplate 2. This stress, actingnormal to the baseplate surface 2 a, must be overcome (reversed) beforeany load applied to the shoulder 1 can succeed in lifting the shoulder 1from the baseplate 2. The assembled shoulder 1 and baseplate 2 are shownin FIGS. 8, 10 and 11. Retention of the shoulder 1 on the baseplate 2 isassisted by frictional resistance between the boss 11 and the baseplatematerial in contact with it, and by the steel forced into the grooves 12in the boss 11 which is in shear at the interface between the boss 11and the baseplate 2. Although FIG. 1 and related Figures show a shoulder1 having a plurality of grooves 12, a method embodying the first aspectof the invention could usefully employ a boss 11 without any grooves 12or other recesses, in which case the clamping force between the shoulder1 and baseplate 2 would not be as great. Preferably, however, a boss 11having a single, coarser groove may be used instead, as shown in FIG.12, and in fact such an arrangement is likely to be more effective thana plurality of grooves and would be easier to manufacture. FIG. 12 showsa section through a baseplate 2, to which a shoulder 1 had been attachedusing a method embodying the first aspect of the present invention andhas now been removed following cutting of the baseplate 2. An indent 22left by the action of the penetrating tool 3 on the bottom face 2 b ofthe baseplate 2 can be seen. A groove 12 having a modified buttressthread profile, where the direction of axial loading is opposite indirection to a normal buttress thread, is preferred, as shown in FIG. 9.Typical values for the dimensions and angles of the groove 12 shown inFIG. 9 are: a=6.96 mm, b=4.00 mm, c=1.70 mm, d=1.20 mm, e=0.50 mm,A=87°, B=58° and C=35°.

1. A method of attaching a steel railway rail support to a ductile ironrail clip anchoring device, which method comprises: inserting a boss,protruding from the bottom of a body of the anchoring device, into ahole passing through the support at a location on its surface at whichthe anchoring device is to be attached until the anchoring device bodyabuts the support surface; and compressing the steel around the hole ina region on the support surface opposite to that on which the anchoringdevice body is located, while the anchoring device is held in place, sothat the compressed steel flows plastically against the boss within thehole, until the force thereby applied to the boss brings aboutelongation thereof, whereby the boss undergoes an elastic set whichclamps the boss to the support..
 2. A method as claimed in claim 1,wherein the boss is provided with at least one recess in its flank andthe compressed steel also flows plastically into the said recess.
 3. Amethod as claimed in claim 2, wherein the recess comprises a singlenon-helical groove extending around the boss.
 4. A method as claimed inclaim 2, wherein the flank of the boss is provided with a plurality ofrecesses, each comprising a non-helical groove extending around theboss.
 5. A method as claimed in claim 1, wherein the step of compressingthe steel around the hole is performed by applying a penetrating tool,having a working face of a desired shape, to the surface of the supportopposite to that on which the anchoring device body is located until thetool has entered the support surface for a desired distance.
 6. A methodas claimed in claim 5, wherein the said penetrating tool is shaped toallow the said elongation of the boss.
 7. A method as claimed in claim1, wherein the step of inserting the boss into the hole in the supportis performed by supporting the anchoring device so that the boss extendsupwardly and then lowering the support such that the boss passes throughthe hole.
 8. A method as claimed in claim 1, wherein the support isprovided with two such holes and the method is carried outsimultaneously with respect to both holes thereby to attach twoanchoring devices to the support.
 9. A method as claimed in claim 1,wherein the said hole or holes are punched into the steel support.
 10. Amethod as claimed in claim 1, wherein the said railway rail support is arailway sleeper.
 11. A method as claimed in claim 1, wherein the saidrailway rail support is a railway rail baseplate.
 12. A rail clipanchoring device, for use with the method of claim 1, which device hasan anchoring device body and, protruding from the bottom of that body, aboss provided with at least one recess in its flank, the recesscomprising a single non-helical groove extending around the boss.
 13. Adevice as claimed in claim 12, wherein the flank of the boss is providedwith a plurality of such recesses.
 14. A device as claimed in claim 12,wherein the profile of the or each groove is substantially that of abuttress thread.
 15. A device as claimed in claim 12, wherein the oreach recess is provided adjacent a free end of the boss.
 16. A railwayrail fastening assembly comprising a steel railway rail support, havingtwo holes therethrough, and two ductile iron rail clip anchoringdevices, each anchoring device having an anchoring device body and,protruding from the bottom of that body, a boss which extends into arespective one of the said holes in the support, the boss of eachanchoring device having an elastic set whereby the boss is clamped tothe support, wherein the boss of at least one of the anchoring deviceshas at least one recess provided in its flank, the recess comprising asingle non-helical groove extending around the boss.
 17. An assembly asclaimed in claim 16, wherein the flank of the boss is provided with aplurality of such recesses.
 18. An assembly as claimed in claim 16,wherein the profile of the or each groove is substantially that of abuttress thread.
 19. An assembly as claimed in claim 16, wherein the oreach recess is provided adjacent a free end of the boss.
 20. An assemblyas claimed in claim 16, wherein the said railway rail support is arailway sleeper.
 21. An assembly as claimed in claim 16, wherein thesaid railway rail support is a railway rail baseplate.